This invention relates generally to presses and, more particularly, to reciprocating press construction of the box and piston type such as, for example, rectangular balers.
Some rectangular balers, which are towed vehicles, derive their operating power from a power take-off shaft connected to the towing vehicle, such as an agricultural tractor. The power take-off shaft provides power to a main drive gearbox which in turn directly drives a plunger and, by means of a drive element, such as a chain or belt or the like, a drive member off the gearbox translates power to a driven member to operate the feeder, knotter and pickup functions of the baler. Thus, significant inertial energy is translated via the drive element from the drive member to the driven member.
With such inertial energy present, should the drive member suddenly stop because, for example, the baler plunger strikes a foreign object or because the crank arm strikes a needle safety latch due to the mistiming of the feeder, the translated inertial energy causes the driven member to overrun the drive member. As a result, the normally slack side of the chain is snapped taut resulting in premature chain failures or causing the idler mechanism to bottom out and possibly be damaged. The idler is able to bottom out under these conditions since the single spring normally used in such idler mechanisms is a relatively light spring provided only to limit slack in the chain or belt.
The foregoing illustrates limitations of the known prior art. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations as set forth above.